Is she playing hard to get?

There's this girl I really like. About a year ago, I was friendzoned by her, because I was a huge awkward penguin. After a year later, I met her again from a charity organisation we are involved in, and she says I've become "taller, slimmer and buffer" (her exact words). Anyway, she seems to have taken a bit more interest in me now that I've opened up more as a person. I've asked her out, (the date is in a weeks time), with her answer being "YES sure text me,". So I texted her, and I realised that whenever we text on whatsapp, she completely ignores my messages, and only replies after a few hours with a cheerful text. I'm sure she's not ignoring me because she finds me annoying and stuff, firstly because her texts are cheerful and fun, secondly because if she REALLY didn't like me, she would've never even replied. The thing is, I KNOW she's online on whatsapp because she was posting on the charity whatsapp group, like she KNOWS I will see it, and WANTS me to see it. She just doesn't want to reply me. This has been going on for a while now. I even gave her a call, and she answered the call after a short while, and we had a wonderful lively conversation with a lot of flirting and jokes. I'm just confused about the texting part. She has been known to take the inititative with guys, and if she did have interest, I feel she wouldn't have wasted quality talking time with me, someone who obviously would like her back. Could she be playing hard to get?